title: Socioeconomic measures and CKD in the United States and The Netherlands.
abstract: OBJECTIVE
  According to the cost of health care utilization systems, there may be regional differences in the relative strength of association of income and education-based socioeconomic status measures with CKD. This study investigated the relative strength of the association of income and education with CKD in a United States and a Dutch population.
  
  
  METHODS
  This cross-sectional study examined individuals who participated in the 1999-2002 National Health and Nutritional Examination Survey (NHANES) and in Prevention of Renal and Vascular End-stage Disease (PREVEND 1997-1998), general population-based cohorts in the United States and The Netherlands, respectively. The main outcome was CKD, defined as estimated GFR <60 ml/min per 1.73 m(2) (using creatinine) or albuminuria ≥ 30 mg/24 hours or albumin-to-creatinine ratio ≥ 30 mg/g.
  
  
  RESULTS
  In NHANES (n=6428), income was strongly associated with CKD (adjusted odds ratio, 2.34 [95% confidence interval (CI), 1.68 to 3.27]; P for trend<0.001) but education was not (adjusted odds ratio, 1.62 [95% CI, 0.87 to 2.25]; P for trend=0.05]. In contrast, in PREVEND (n=7983), low income was weakly associated with CKD whereas low education had a strong association. The fit of the logistic regression model estimating association of income and education with CKD was significantly improved only after income was added in NHANES (P<0.001) and education was added in PREVEND (P=0.01). Sensitivity analyses that used other CKD-defining variables and restricted analyses to participants <65 years of age resulted in similar findings.
  
  
  CONCLUSIONS
  In the United States, where access to health care is traditionally income dependent, income appeared more strongly associated with CKD than in The Netherlands, where education showed a stronger association.
authors.affiliation: Department of Health Sciences, Community and Occupational Medicine and, †Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands, and, ‡Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
authors.forename: Priya
authors.initials: P
authors.lastname: Vart
authors.forename: Ron T
authors.initials: RT
authors.lastname: Gansevoort
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.forename: Sijmen A
authors.initials: SA
authors.lastname: Reijneveld
authors.forename: Ute
authors.initials: U
authors.lastname: Bültmann
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012923:Social Class; D014481:United States / Q000453:epidemiology